I found this via google... on tire rack... basically sounds like you need to watch how your tire wears and only worry about it if you feel a vibration or excessive tire wear.


The GSP9700 Vibration Control System includes Hunter's exclusive Road Force Measurement System to help detect potential tire uniformity causes of vibration that are not balance-related. This system utilizes a "road roller" which applies up to 1,400 pounds (635 kg) of force against the wheel and tire assembly to measure their combined uniformity. This simulated road force test helps verify if the assembly is "round" when rolling under load.

tire rack article